MECP2 mutant allele in a boy with Rett syndrome and his unaffected heterozygous mother

Brain Dev. 2007 Jan;29(1):47-50. doi: 10.1016/j.braindev.2006.06.001. Epub 2006 Jul 17.


Rett syndrome is a severe neurodevelopmental disorder affecting principally females and characterized by a normal postnatal development followed by stagnation and regression of acquired skills. We report a 4-year-old boy with a Rett syndrome phenotype and his unaffected mother both carrying a 44 bp truncating deletion mutation (c.1158del44 or p.388X) in the MECP2 gene. The presence of a skewed X inactivation in the mother provides a possible explanation for the absence of penetrance. The finding of a MECP2 mutation in an unaffected female complicates genetic counseling and further confirms that it is essential to look for mutations in the mothers of all patients with MECP2 mutations.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Child, Preschool
  • DNA Mutational Analysis
  • Female
  • Gene Deletion
  • Gene Frequency / genetics
  • Genetic Diseases, X-Linked / genetics*
  • Genetic Predisposition to Disease / genetics*
  • Genetic Testing
  • Heterozygote
  • Humans
  • Inheritance Patterns / genetics*
  • Male
  • Methyl-CpG-Binding Protein 2 / genetics*
  • Mothers
  • Mutation / genetics*
  • Penetrance
  • Phenotype
  • Rett Syndrome / diagnosis
  • Rett Syndrome / genetics*
  • X Chromosome Inactivation / genetics


  • MECP2 protein, human
  • Methyl-CpG-Binding Protein 2